// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_APP_LIST_VIEWS_APPS_GRID_VIEW_H_
#define UI_APP_LIST_VIEWS_APPS_GRID_VIEW_H_

#include <stddef.h>

#include <set>
#include <string>
#include <tuple>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/timer/timer.h"
#include "build/build_config.h"
#include "ui/app_list/app_list_export.h"
#include "ui/app_list/app_list_model.h"
#include "ui/app_list/app_list_model_observer.h"
#include "ui/app_list/pagination_model.h"
#include "ui/app_list/pagination_model_observer.h"
#include "ui/base/models/list_model_observer.h"
#include "ui/compositor/layer_animation_observer.h"
#include "ui/gfx/image/image_skia_operations.h"
#include "ui/views/animation/bounds_animator.h"
#include "ui/views/controls/button/button.h"
#include "ui/views/controls/image_view.h"
#include "ui/views/view.h"
#include "ui/views/view_model.h"

#if defined(OS_WIN)
#include "ui/base/dragdrop/drag_source_win.h"
#include <wrl/client.h>
#endif

namespace views {
class ButtonListener;
class DragImageView;
}

namespace app_list {

#if defined(OS_WIN)
class SynchronousDrag;
#endif

namespace test {
    class AppsGridViewTestApi;
}

class ApplicationDragAndDropHost;
class AppListItemView;
class AppsGridViewDelegate;
class AppsGridViewFolderDelegate;
class PageSwitcher;
class PaginationController;
class PulsingBlockView;

// AppsGridView displays a grid for AppListItemList sub model.
class APP_LIST_EXPORT AppsGridView : public views::View,
                                     public views::ButtonListener,
                                     public AppListItemListObserver,
                                     public PaginationModelObserver,
                                     public AppListModelObserver,
                                     public ui::ImplicitAnimationObserver {
public:
    enum Pointer {
        NONE,
        MOUSE,
        TOUCH,
    };

    // Constructs the app icon grid view. |delegate| is the delegate of this
    // view, which usually is the hosting AppListView.
    explicit AppsGridView(AppsGridViewDelegate* delegate);
    ~AppsGridView() override;

    // Sets fixed layout parameters. After setting this, CalculateLayout below
    // is no longer called to dynamically choosing those layout params.
    void SetLayout(int cols, int rows_per_page);

    int cols() const { return cols_; }
    int rows_per_page() const { return rows_per_page_; }

    // Returns the size of a tile view including its padding.
    static gfx::Size GetTotalTileSize();

    // This resets the grid view to a fresh state for showing the app list.
    void ResetForShowApps();

    // Sets |model| to use. Note this does not take ownership of |model|.
    void SetModel(AppListModel* model);

    // Sets the |item_list| to render. Note this does not take ownership of
    // |item_list|.
    void SetItemList(AppListItemList* item_list);

    void SetSelectedView(AppListItemView* view);
    void ClearSelectedView(AppListItemView* view);
    void ClearAnySelectedView();
    bool IsSelectedView(const AppListItemView* view) const;
    bool has_selected_view() const { return selected_view_ != nullptr; }

    void InitiateDrag(AppListItemView* view,
        Pointer pointer,
        const ui::LocatedEvent& event);

    // Called from AppListItemView when it receives a drag event. Returns true
    // if the drag is still happening.
    bool UpdateDragFromItem(Pointer pointer, const ui::LocatedEvent& event);

    // Called when the user is dragging an app. |point| is in grid view
    // coordinates.
    void UpdateDrag(Pointer pointer, const gfx::Point& point);
    void EndDrag(bool cancel);
    bool IsDraggedView(const AppListItemView* view) const;
    void ClearDragState();
    void SetDragViewVisible(bool visible);

    // Set the drag and drop host for application links.
    void SetDragAndDropHostOfCurrentAppList(
        ApplicationDragAndDropHost* drag_and_drop_host);

    // Prerenders the icons on and around the currently selected page.
    void Prerender();

    // Return true if the |bounds_animator_| is animating |view|.
    bool IsAnimatingView(AppListItemView* view);

    bool has_dragged_view() const { return drag_view_ != nullptr; }
    bool dragging() const { return drag_pointer_ != NONE; }

    // Gets the PaginationModel used for the grid view.
    PaginationModel* pagination_model() { return &pagination_model_; }

    // Overridden from views::View:
    gfx::Size GetPreferredSize() const override;
    void Layout() override;
    bool OnKeyPressed(const ui::KeyEvent& event) override;
    bool OnKeyReleased(const ui::KeyEvent& event) override;
    bool OnMouseWheel(const ui::MouseWheelEvent& event) override;
    void ViewHierarchyChanged(
        const ViewHierarchyChangedDetails& details) override;
    bool GetDropFormats(
        int* formats,
        std::set<ui::Clipboard::FormatType>* format_types) override;
    bool CanDrop(const OSExchangeData& data) override;
    int OnDragUpdated(const ui::DropTargetEvent& event) override;

    // Overridden from ui::EventHandler:
    void OnGestureEvent(ui::GestureEvent* event) override;
    void OnScrollEvent(ui::ScrollEvent* event) override;

    // Stops the timer that triggers a page flip during a drag.
    void StopPageFlipTimer();

    // Returns the item view of the item at |index|.
    AppListItemView* GetItemViewAt(int index) const;

    // Show or hide the top item views.
    void SetTopItemViewsVisible(bool visible);

    // Schedules an animation to show or hide the view.
    void ScheduleShowHideAnimation(bool show);

    // Called to initiate drag for reparenting a folder item in root level grid
    // view.
    // Both |drag_view_rect| and |drag_pint| is in the coordinates of root level
    // grid view.
    void InitiateDragFromReparentItemInRootLevelGridView(
        AppListItemView* original_drag_view,
        const gfx::Rect& drag_view_rect,
        const gfx::Point& drag_point,
        bool has_native_drag);

    // Updates drag in the root level grid view when receiving the drag event
    // dispatched from the hidden grid view for reparenting a folder item.
    void UpdateDragFromReparentItem(Pointer pointer,
        const gfx::Point& drag_point);

    // Dispatches the drag event from hidden grid view to the top level grid view.
    void DispatchDragEventForReparent(Pointer pointer,
        const gfx::Point& drag_point);

    // Handles EndDrag event dispatched from the hidden folder grid view in the
    // root level grid view to end reparenting a folder item.
    // |events_forwarded_to_drag_drop_host|: True if the dragged item is dropped
    // to the drag_drop_host, eg. dropped on shelf.
    // |cancel_drag|: True if the drag is ending because it has been canceled.
    void EndDragFromReparentItemInRootLevel(
        bool events_forwarded_to_drag_drop_host,
        bool cancel_drag);

    // Handles EndDrag event in the hidden folder grid view to end reparenting
    // a folder item.
    void EndDragForReparentInHiddenFolderGridView();

    // Called when the folder item associated with the grid view is removed.
    // The grid view must be inside a folder view.
    void OnFolderItemRemoved();

    // Return the view model for test purposes.
    const views::ViewModelT<AppListItemView>* view_model_for_test() const
    {
        return &view_model_;
    }

    // For test: Return if the drag and drop handler was set.
    bool has_drag_and_drop_host_for_test()
    {
        return nullptr != drag_and_drop_host_;
    }

    // For test: Return if the drag and drop operation gets dispatched.
    bool forward_events_to_drag_and_drop_host_for_test()
    {
        return forward_events_to_drag_and_drop_host_;
    }

    void set_folder_delegate(AppsGridViewFolderDelegate* folder_delegate)
    {
        folder_delegate_ = folder_delegate;
    }

    AppListItemView* activated_folder_item_view() const
    {
        return activated_folder_item_view_;
    }

    const AppListModel* model() const { return model_; }

private:
    friend class test::AppsGridViewTestApi;

    enum DropAttempt {
        DROP_FOR_NONE,
        DROP_FOR_REORDER,
        DROP_FOR_FOLDER,
    };

    // Represents the index to an item view in the grid.
    struct Index {
        Index()
            : page(-1)
            , slot(-1)
        {
        }
        Index(int page, int slot)
            : page(page)
            , slot(slot)
        {
        }

        bool operator==(const Index& other) const
        {
            return page == other.page && slot == other.slot;
        }
        bool operator!=(const Index& other) const
        {
            return page != other.page || slot != other.slot;
        }
        bool operator<(const Index& other) const
        {
            return std::tie(page, slot) < std::tie(other.page, other.slot);
        }

        int page; // Which page an item view is on.
        int slot; // Which slot in the page an item view is in.
    };

    int tiles_per_page() const { return cols_ * rows_per_page_; }

    // Updates from model.
    void Update();

    // Updates page splits for item views.
    void UpdatePaging();

    // Updates the number of pulsing block views based on AppListModel status and
    // number of apps.
    void UpdatePulsingBlockViews();

    AppListItemView* CreateViewForItemAtIndex(size_t index);

    // Convert between the model index and the visual index. The model index
    // is the index of the item in AppListModel. The visual index is the Index
    // struct above with page/slot info of where to display the item.
    Index GetIndexFromModelIndex(int model_index) const;
    int GetModelIndexFromIndex(const Index& index) const;

    // Ensures the view is visible. Note that if there is a running page
    // transition, this does nothing.
    void EnsureViewVisible(const Index& index);

    void SetSelectedItemByIndex(const Index& index);
    bool IsValidIndex(const Index& index) const;

    Index GetIndexOfView(const AppListItemView* view) const;
    AppListItemView* GetViewAtIndex(const Index& index) const;

    // Gets the index of the AppListItemView at the end of the view model.
    Index GetLastViewIndex() const;

    void MoveSelected(int page_delta, int slot_x_delta, int slot_y_delta);

    void CalculateIdealBounds();
    void AnimateToIdealBounds();

    // Invoked when the given |view|'s current bounds and target bounds are on
    // different rows. To avoid moving diagonally, |view| would be put into a
    // slot prior |target| and fade in while moving to |target|. In the meanwhile,
    // a layer copy of |view| would start at |current| and fade out while moving
    // to succeeding slot of |current|. |animate_current| controls whether to run
    // fading out animation from |current|. |animate_target| controls whether to
    // run fading in animation to |target|.
    void AnimationBetweenRows(AppListItemView* view,
        bool animate_current,
        const gfx::Rect& current,
        bool animate_target,
        const gfx::Rect& target);

    // Extracts drag location info from |event| into |drag_point|.
    void ExtractDragLocation(const ui::LocatedEvent& event,
        gfx::Point* drag_point);

    // Updates |reorder_drop_target_|, |folder_drop_target_| and |drop_attempt_|
    // based on |drag_view_|'s position.
    void CalculateDropTarget();

    // If |point| is a valid folder drop target, returns true and sets
    // |drop_target| to the index of the view to do a folder drop for.
    bool CalculateFolderDropTarget(const gfx::Point& point,
        Index* drop_target) const;

    // Calculates the reorder target |point| and sets |drop_target| to the index
    // of the view to reorder.
    void CalculateReorderDropTarget(const gfx::Point& point,
        Index* drop_target) const;

    // Prepares |drag_and_drop_host_| for dragging. |grid_location| contains
    // the drag point in this grid view's coordinates.
    void StartDragAndDropHostDrag(const gfx::Point& grid_location);

    // Dispatch the drag and drop update event to the dnd host (if needed).
    void DispatchDragEventToDragAndDropHost(
        const gfx::Point& location_in_screen_coordinates);

    // Starts the page flip timer if |drag_point| is in left/right side page flip
    // zone or is over page switcher.
    void MaybeStartPageFlipTimer(const gfx::Point& drag_point);

    // Invoked when |page_flip_timer_| fires.
    void OnPageFlipTimer();

    // Updates |model_| to move item represented by |item_view| to |target| slot.
    void MoveItemInModel(AppListItemView* item_view, const Index& target);

    // Updates |model_| to move item represented by |item_view| into a folder
    // containing item located at |target| slot, also update |view_model_| for
    // the related view changes.
    void MoveItemToFolder(AppListItemView* item_view, const Index& target);

    // Updates both data model and view_model_ for re-parenting a folder item to a
    // new position in top level item list.
    void ReparentItemForReorder(AppListItemView* item_view, const Index& target);

    // Updates both data model and view_model_ for re-parenting a folder item
    // to anther folder target. Returns whether the reparent succeeded.
    bool ReparentItemToAnotherFolder(AppListItemView* item_view,
        const Index& target);

    // If there is only 1 item left in the source folder after reparenting an item
    // from it, updates both data model and view_model_ for removing last item
    // from the source folder and removes the source folder.
    void RemoveLastItemFromReparentItemFolderIfNecessary(
        const std::string& source_folder_id);

    // If user does not drop the re-parenting folder item to any valid target,
    // cancel the re-parenting action, let the item go back to its original
    // parent folder with UI animation.
    void CancelFolderItemReparent(AppListItemView* drag_item_view);

    // Cancels any context menus showing for app items on the current page.
    void CancelContextMenusOnCurrentPage();

    // Removes the AppListItemView at |index| in |view_model_| and deletes it.
    void DeleteItemViewAtIndex(int index);

    // Returns true if |point| lies within the bounds of this grid view plus a
    // buffer area surrounding it.
    bool IsPointWithinDragBuffer(const gfx::Point& point) const;

    // Overridden from views::ButtonListener:
    void ButtonPressed(views::Button* sender, const ui::Event& event) override;

    // Overridden from AppListItemListObserver:
    void OnListItemAdded(size_t index, AppListItem* item) override;
    void OnListItemRemoved(size_t index, AppListItem* item) override;
    void OnListItemMoved(size_t from_index,
        size_t to_index,
        AppListItem* item) override;
    void OnAppListItemHighlight(size_t index, bool highlight) override;

    // Overridden from PaginationModelObserver:
    void TotalPagesChanged() override;
    void SelectedPageChanged(int old_selected, int new_selected) override;
    void TransitionStarted() override;
    void TransitionChanged() override;

    // Overridden from AppListModelObserver:
    void OnAppListModelStatusChanged() override;

    // ui::ImplicitAnimationObserver overrides:
    void OnImplicitAnimationsCompleted() override;

    // Hide a given view temporarily without losing (mouse) events and / or
    // changing the size of it. If |immediate| is set the change will be
    // immediately applied - otherwise it will change gradually.
    // If |hide| is set the view will get hidden, otherwise it gets shown.
    void SetViewHidden(AppListItemView* view, bool hide, bool immediate);

    // Whether the folder drag-and-drop UI should be enabled.
    bool EnableFolderDragDropUI();

    // Returns the size of the entire tile grid.
    gfx::Size GetTileGridSize() const;

    // Returns the slot number which the given |point| falls into or the closest
    // slot if |point| is outside the page's bounds.
    Index GetNearestTileIndexForPoint(const gfx::Point& point) const;

    // Gets the bounds of the tile located at |slot| on the current page.
    gfx::Rect GetExpectedTileBounds(int slot) const;

    // Gets the bounds of the tile located at |row| and |col| on the current page.
    gfx::Rect GetExpectedTileBounds(int row, int col) const;

    // Gets the item view currently displayed at |slot| on the current page. If
    // there is no item displayed at |slot|, returns NULL. Note that this finds an
    // item *displayed* at a slot, which may differ from the item's location in
    // the model (as it may have been temporarily moved during a drag operation).
    AppListItemView* GetViewDisplayedAtSlotOnCurrentPage(int slot) const;

    // Sets state of the view with |target_index| to |is_target_folder| for
    // dropping |drag_view_|.
    void SetAsFolderDroppingTarget(const Index& target_index,
        bool is_target_folder);

    // Invoked when |reorder_timer_| fires to show re-order preview UI.
    void OnReorderTimer();

    // Invoked when |folder_item_reparent_timer_| fires.
    void OnFolderItemReparentTimer();

    // Invoked when |folder_dropping_timer_| fires to show folder dropping
    // preview UI.
    void OnFolderDroppingTimer();

    // Updates drag state for dragging inside a folder's grid view.
    void UpdateDragStateInsideFolder(Pointer pointer,
        const gfx::Point& drag_point);

    // Returns true if drag event is happening in the root level AppsGridView
    // for reparenting a folder item.
    bool IsDraggingForReparentInRootLevelGridView() const;

    // Returns true if drag event is happening in the hidden AppsGridView of the
    // folder during reparenting a folder item.
    bool IsDraggingForReparentInHiddenGridView() const;

    // Returns the target icon bounds for |drag_item_view| to fly back
    // to its parent |folder_item_view| in animation.
    gfx::Rect GetTargetIconRectInFolder(AppListItemView* drag_item_view,
        AppListItemView* folder_item_view);

    // Returns true if the grid view is under an OEM folder.
    bool IsUnderOEMFolder();

    void StartSettingUpSynchronousDrag();
    bool RunSynchronousDrag();
    void CleanUpSynchronousDrag();
#if defined(OS_WIN)
    void OnGotShortcutPath(Microsoft::WRL::ComPtr<SynchronousDrag> drag,
        const base::FilePath& path);
#endif

    AppListModel* model_; // Owned by AppListView.
    AppListItemList* item_list_; // Not owned.
    AppsGridViewDelegate* delegate_;

    // This can be NULL. Only grid views inside folders have a folder delegate.
    AppsGridViewFolderDelegate* folder_delegate_;

    PaginationModel pagination_model_;
    // Must appear after |pagination_model_|.
    scoped_ptr<PaginationController> pagination_controller_;
    PageSwitcher* page_switcher_view_; // Owned by views hierarchy.

    int cols_;
    int rows_per_page_;

    // List of app item views. There is a view per item in |model_|.
    views::ViewModelT<AppListItemView> view_model_;

    // List of pulsing block views.
    views::ViewModelT<PulsingBlockView> pulsing_blocks_model_;

    AppListItemView* selected_view_;

    AppListItemView* drag_view_;

    // The index of the drag_view_ when the drag starts.
    Index drag_view_init_index_;

    // The point where the drag started in AppListItemView coordinates.
    gfx::Point drag_view_offset_;

    // The point where the drag started in GridView coordinates.
    gfx::Point drag_start_grid_view_;

    // The location of |drag_view_| when the drag started.
    gfx::Point drag_view_start_;

    // Page the drag started on.
    int drag_start_page_;

#if defined(OS_WIN)
    // Created when a drag is started (ie: drag exceeds the drag threshold), but
    // not Run() until supplied with a shortcut path.
    Microsoft::WRL::ComPtr<SynchronousDrag> synchronous_drag_;

    // Whether to use SynchronousDrag to support dropping to task bar etc.
    bool use_synchronous_drag_;
#endif

    Pointer drag_pointer_;

    // The most recent reorder drop target.
    Index reorder_drop_target_;

    // The most recent folder drop target.
    Index folder_drop_target_;

    // The index where an empty slot has been left as a placeholder for the
    // reorder drop target. This updates when the reorder animation triggers.
    Index reorder_placeholder_;

    // The current action that ending a drag will perform.
    DropAttempt drop_attempt_;

    // Timer for re-ordering the |drop_target_| and |drag_view_|.
    base::OneShotTimer reorder_timer_;

    // Timer for dropping |drag_view_| into the folder containing
    // the |drop_target_|.
    base::OneShotTimer folder_dropping_timer_;

    // Timer for dragging a folder item out of folder container ink bubble.
    base::OneShotTimer folder_item_reparent_timer_;

    // An application target drag and drop host which accepts dnd operations.
    ApplicationDragAndDropHost* drag_and_drop_host_;

    // The drag operation is currently inside the dnd host and events get
    // forwarded.
    bool forward_events_to_drag_and_drop_host_;

    // Last mouse drag location in this view's coordinates.
    gfx::Point last_drag_point_;

    // Timer to auto flip page when dragging an item near the left/right edges.
    base::OneShotTimer page_flip_timer_;

    // Target page to switch to when |page_flip_timer_| fires.
    int page_flip_target_;

    // Delay in milliseconds of when |page_flip_timer_| should fire after user
    // drags an item near the edges.
    int page_flip_delay_in_ms_;

    views::BoundsAnimator bounds_animator_;

    // The most recent activated folder item view.
    AppListItemView* activated_folder_item_view_;

    // Tracks if drag_view_ is dragged out of the folder container bubble
    // when dragging a item inside a folder.
    bool drag_out_of_folder_container_;

    // True if the drag_view_ item is a folder item being dragged for reparenting.
    bool dragging_for_reparent_item_;

    DISALLOW_COPY_AND_ASSIGN(AppsGridView);
};

} // namespace app_list

#endif // UI_APP_LIST_VIEWS_APPS_GRID_VIEW_H_
